This invention relates to a hinge for securing two adjacent door panels of an airplane cargo container so that the panels may fold in one direction only and end up parallel to one another.
Airplane cargo containers specifically configured to fit inside the fuselage of an airplane have been used for years. U.S. Pat. No. 4,747,504 assigned to Airborne Express, Inc. discloses one such aircraft cargo container. This patent discloses a three-panel door slidably mounted in channels to enable the door to fold in an accordion fashion and be stored above the container when not in use. An upper panel is secured to an intermediate panel with a piano-type hinge, and similarly the intermediate panel is secured to a lower panel with another piano-type hinge. The piano-type hinges are located on opposite sides of the door. The door panels may be folded upon one another in order to fully open, partially open, or close an opening at the front of the container. However, these piano-type hinges are not structurally strong enough to withstand common loads placed upon the door which may be up to 2000 pounds of pressure. Additionally, these piano-type hinges are expensive to apply to the door because they require many rivets applied to the panels of the door. Thus, to apply a piano-type hinge to a door panel is very labor intensive. Additionally, the rivets used to secure the piano-type hinges to the door panels may wear over time, causing the hinges to be easily torn off the door panels.
Consequently, it is one objective of the present invention to provide a hinge for use with container doors which will withstand large loads.
It is a further objective of the present invention to provide a hinge which enables two door panels to fold in one direction only. It is a further objective of the present invention to provide a hinge which connects two door panels without the use of rivets.
The invention of this application which accomplishes these objectives comprises a hinge for joining two adjacent door panels. The hinge may be used in many other applications and is not intended to be limited to use with airplane container door panels.
The hinge comprises a first piece adapted to receive a first door panel, a second piece adapted to receive a second door panel, and a middle piece joining the first and second pieces so that the first and second pieces, along with their respective panels, can only be folded in one direction. Each of the first and second pieces has an opening for receiving a door panel and a socket defined between two spaced stopping surfaces. The openings may be any size or configuration in order to receive panels of different thicknesses and configurations. Each of the stopping surfaces is essentially planar and extends the width of the door panel to which the piece is attached.
The middle piece has a pair of cylindrical sections at the outer ends of arms extending radially outward from a central section of the middle piece. Each of the arms has an outer surface and an inner surface. One of the cylindrical sections of the middle piece of the hinge is received within the socket of the first piece of the hinge. The other of the cylindrical sections of the middle piece of the hinge is received within the socket of the second piece of the hinge. Each of the cylindrical sections has a circular cross sectional configuration.
Interengagement of the stopping surfaces of the first and second pieces of the hinge with the arms of the middle piece of the hinge prevents the door panels from folding in one direction but enables the door panels to fold in the other direction together so that they are substantially parallel (side by side). The stopping surfaces of the first and second pieces of the hinge abut the outer surface of the arms of the middle piece of the hinge when the panels are opened, thus preventing the door panels from folding in one direction while enabling the door panels to fold in the other direction. When the door panels are closed or folded together, the stopping surfaces of the first and second pieces of the hinge abut an inner surface of the arms of the middle piece of the hinge.